60 COLLEMACEI. [COLLEMODIUM. 



otherwise as in the type. Leptoyium plicatile f. minor Cromb. Journ. 

 Bot. 1874, p. 336 ; Leight. Lich. Fl. ed. 3, p. 31. 



This form evidently depends upon the nature of the habitat. It is 

 rarely fertile. 



Hab. In depressions of dry roc-ks in maritime and upland tracts. 

 Distr. Local and rare in the S.W. Highlands of Scotland and in S.W. 

 Ireland. B. M. : Island of Lismore, Argyleshire. Near Killarney, co. 

 Kerry. 



Var. /3. hydrocharum Nyl. ex Croinb. Grevillea, xv. (1886) p. 12. 



Thallus thicker, rigid, greyish- or glaucous-greyish ; lobes repand, 



somewhat rugulose, depressed. Apothecia central, scattered, the 

 thalline margin entire. Leptogium plicatile var. hydrochamm Nyl. 

 Flora, 1875, p. 302. Collema pulposum var. hydrochamm Cromb. 

 Journ. Bot. 1874, p. 147 ; Leight. Lich. Fl. ed. 3, p. 18. ParmeKa 

 hydrocharum Ach. Mefch. (1803) p. 222. 



Distinguished by the colour of the thicker thallus and the more de- 

 pressed lobes, which are somewhat discrete at the circumference. No 

 fructification is visible in our only British specimen. 



Hub. On damp calcareous rocks in upland districts. Distr. Only 

 among the Central Grampians, Scotland. B. M. : .Craig Tulloch, Perth- 

 shire. 



5. C. fluviatile Nyl. ex Cromb. Grevillea, xv. (1886) p. 12. 

 Thallus inciso-lobed, thin, greyish-green or dark greyish-glaucous ; 

 lobes somewhat erect, oblong, subrepand, flexuoso-coraplicate, simple 

 or proliferous. Apothecia small, submarginal, elevated, plane or 

 somewhat concave, dark-red, the thalline margin entire, paler ; 

 spores ellipsoid, usually 3-septate, 0,016-23 mm. long, 0,007-9 mm. 

 thick. Leptogium fluviatile Nyl. ex Cromb. Journ. Bot. 1874, 

 p. 336 ; Leight. Lich. Fl. ed. 3, p. 32. Collema fluviatile Sm. Eng. 

 Fl. v. p. 209 ; Mudd, Man. p. 40 ; Cromb. Lich. Brit. p. 5 ; Leight. 

 Lich. Fl. p. 24. Collema multipartitum ft. fluviatile Tayl. in Fl. 

 Hib. ii. p. 109. Enchylium fluviale Gray, Nat. Arr. i. p. 397. 

 Lichen fluviatilis Huds. Fl. Angl. ed. 2 (1778), p. 536 ; With. Arr. 

 ed. 3, iv. p. 77 ; Eng. Bot. t. 2039. Lichenoid.es gelatinosum foliis 

 angustioribus tunafoiinibus Dill. Muse. 142, t. 19. f. 28. Liche- 

 noides gelatinosum opuntioides Dill, in Hay, Syn. ed. 3, 72. 58. 



This approaches in habit small states of Leptogium tremelloides. It is 

 distinguished from the preceding species by the form of the lobes and of 

 the smaller spores. In texture, as observed by Nylander (Syn. i. p. 112), 

 the thallus is entirely cellular, the cortex being composed of spheroid 

 cells, with the gonimia either single or usually 4- agglomerate in each 

 cavity. Only a few of the British specimens seen are sparingly fertile. 

 Collema rivulare Ach., according to Nylander in litt., is only a state of this 

 with shorter and simple lobes ; this state occurs in this country. 



Hub. On moist rocks and boulders of streams in upland mountainous 

 situations. Distr. Found only sparingly in W. and N. England, N. 

 Wales, S.W. and Central Scotland, and S.W. Ireland. B. M.: St. 

 Minver, Cornwall; River Elwy, Denbighshire; Suowdon, Carnarvon- 



